Whats this on my brakes?

[Foxy-jim]

Hi guys,

Started to take apart my rear beam today so that I can do a refurb on it. Going fairly well at the moment. I got to the point of using the slide hammer to release the drivers side trailing arm from the beam and tried to pull it all the wau out, but realised there was a black cable going to the to of the rear caliper.

It isnt the brake line or the handbrake cable as I know what these look like. But it was fixed in with what looked like an allen key bolt. If I knew what it was I would have just removed it, but I just wanted to check that it was before I do this. This is the only think holding me back really from getting it all finished!

Heres a pic...


Thanks in advance

[Jonny b]

Don't know bud take it you havnt got 4 abs have you? Where does it go

[mark_airey]

Looks a lot like an ABS sensor to me mate.............

Don't all ph3 cars have ABS as standard??

[Jonny b]

Probably even the 1.4's

[mark_airey]

*nods* Easy way to work it out, open the bonnet, is there anything between the battery and the passenger headlight?? if there is a box with many small metal pipes connected then you have ABS, if there is an empty space you don't

[Jonny b]

Yeh with big letters saying ABS, though I would have thought a 1.4 would only have 2 wheel abs

[Foxy-jim]

It has an ABS pump. But this rear beam was put on from a gti, so whether the ABS works on the rears I dont know haha. Would I be able to undo this whilst I take the trailing arm out as I dont really want to have to take my discs and calipers off.

[Jonny b]

Have a look at the abs pump if it's 4 wheels it will have 8 pipes iirc or 4 for 2 if you just got 4 just ale it off

[mark_airey]

If the beam if off a GTi then that explains it, is the sensor connected to anything?? or is the wire just cut off?? IIRC they are held in with 1 allen bolt (could be a torx) and a shit load of rust normally to the point where you can't get them out without total destruction in my experience

[Niall]

All ph3s have 4 wheel abs as standard

[Connor]

Its the ABS sensor, if it is plugged in, the plug is near the front beam mounts

Yeah they are Torx mark and usually so rusted over that the bolt will snap and the sensor wont budge lol

[Foxy-jim]

Damn, That best not happen! Haha. Hopefully i can get it out!

EDIT: Also while we are talking about rear beams...I spoke to the mechanic at the garage I use yeaterday and he said something about me needing a different brake valve for my beam to work properly, yet I have had it on for 6 months and not had a problem. He said it may cause it to fail the MOT? Can someone explain please?

[mark_airey]

Damn, That best not happen! Haha. Hopefully i can get it out!

EDIT: Also while we are talking about rear beams...I spoke to the mechanic at the garage I use yeaterday and he said something about me needing a different brake valve for my beam to work properly, yet I have had it on for 6 months and not had a problem. He said it may cause it to fail the MOT? Can someone explain please?

Be gentle with it then

You should really adjust the bias valve (reduces braking force to the rear when there is no load to stop the rear wheels locking) on the beam when you lower them but since it has ABS I don't think it will have one so tell him to stop dishing out bad advice and carry on fixing cars

[Jonny b]

Can you not unplug it at the other end or will that still not work?

[Connor]

I dont have a load valve on my dturbo... or abs...

[Foxy-jim]

Thats what I said. I said it doesnt lock up or anything. Oh well, hopefully it will be ok! He also told me that he will fail me if my car is too low. I was like wtf? Dont know if he like the fact that I have started working on my car myself rather then paying him too!

[mark_airey]

I dont have a load valve on my dturbo... or abs...

Mine might be the same hard braking in the rain can be interesting, gotta be quick with the opposite lock

Thats what I said. I said it doesnt lock up or anything. Oh well, hopefully it will be ok! He also told me that he will fail me if my car is too low. I was like wtf? Dont know if he like the fact that I have started working on my car myself rather then paying him too!

It won't, thats what the ABS is for, the ph3 ABS is much better than the earlier one as in it actually works!

I think this mechanic sounds like a complete jobs worth, tell him to take a f*cking hike, there is nothing wrong at all with what you are doing, tell him that if he doesn't want the work you can always take the car somewhere else to get work done, he might STFU then

[Niall]

He talks out of his arse. The 106s of the same age had a valve that needed adjusting but the 306 actually has brake force distribution which means it will brake 1 wheel if it needs to unlike the 106 which does it per axle

[Foxy-jim]

I thought it would have been alright as the guy who helped fit my beam does everything to the T, and I mean everything. Knew he wouldn't cut corners! Haha.

[cwspellowe]

Phase 3's have electronic brake force distribution. As long as all the ABS sensors are connected and the rear brakes are plumbed in just as the old ones were you'll be fine.

Older 306's have a brake bias compensator valve that regulates rear braking force depending on the load on the axle. A bit primitive tbh and I did away with mine on the GTI6 in favour of a manual brake bias valve.

IIRC to pass an MOT there needs to be a way to adjust braking force front/rear but the tester I used had no idea what a manual bias valve was and passed the car based on its braking efficiency anyway.

[Foxy-jim]

Ok well I'm hoping mine will be ok. The guy just doesn't like my car.

[Toms306]

Pellowes right, all ph3s (yes including 1.4s! and pov specs) have 4 wheel ABS with EBD......so you don't have to adjust anything as its done electronically.

[Foxy-jim]

Wicked, will hopefully pass the mot now!